The authority on patching is Paul Matthews. His book, "The Paper Jacket" is available through Wolfe Publishing (see any gun magazine for their ad). cost is around $12 and is invaluable. Patching isn't nearly as hard as a lot of folks believe, nor do you need batwings or eyes of newts to do it correctly. You can patch smokeless loads just as easily as BP. The limiting factor is velocity, pure lead will disintegrate arround 2,200 f/s. Patch and load using jacketed data since that patch is much slicker than copper. Smokeless cartridges that begged to be patched are the 45-7- and 30-30. That's not to mean that others aren't suitable candidates.